package com.hp.hashmap;

import java.util.HashMap;
import java.util.concurrent.ConcurrentHashMap;

/**
 * @author hp
 */
public class HashMapStudy {

    public static void main(String[] args) {
//        HashMap<String, String> hashMap = new HashMap<>();
        ConcurrentHashMap<String, String> concurrentHashMap = new ConcurrentHashMap<>();

//        hashMap.put("k", "v1");
//        concurrentHashMap.put("k", "v1");
        concurrentHashMap.put(null, null);

    }
}
